As the 2012 London Olympics continue, China and the United States continue to lead the world in medals. China now has a total of 64 medals while the United States has 61.

China has won 31 gold, 19 silver and 14 bronze. The United States has 28 gold, 14 silver and 19 bronze.

In third place, Great Britain with a total of 40; 18 gold, 11 silver and 11 bronze medals. Russia trails them with 37; 5 gold, 17 silver and 15 bronze.

Russia has 27 and have fallen to 5th place. They own 2 gold with 12 silver and 13 bronze medals.

A day after winning a career Grand Slam, Serena Williams has already started thinking about defending her Olympic tennis gold medal at the 2016 Rio de Janeiro Games.

"I plan on being there unless an act of God doesn't allow me to," Williams said Monday.

The 14-time Grand Slam singles champion, who shares the tennis record of four Olympic golds with Venus, has recovered from some health issues that sidelined her for 14 months.

"When I feel I can't be the greatest I shouldn't play anymore, but I feel I belong. I'm not tired. I'm enjoying myself," said the 30-year-old Williams.

Click here for the full medal count list and names of athletes who've won them.